CPAP mask and system

ABSTRACT

A continuous positive air pressure (“CPAP”) or ventilator system includes a mask ( 60 ) and an air flow generator ( 20 ). The air flow generator is mounted or provided to the mask&#39;s wearer. In one embodiment, air flow generator is mounted on the mask.

CROSS-REFERENCE TO PRIORITY APPLICATION

This application is the US national phase of international applicationnumber PCT/AU2004/001309 filed 24 Sep. 2004, which designated the U.S.and claims priority to U.S. Provisional Application No. 60/505,718 filed25 Sep. 2003, the entire contents of each of which are herebyincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to ventilators, e.g., continuous positiveair pressure (“CPAP”) systems comprising a mask and an air flowgenerator, wherein the air flow generator is mountable to the mask'swearer. In one embodiment, the present invention provides CPAP systemswherein an air flow generator is mounted on the mask. In otherembodiments, the air flow generator may be provided to the body of thewearer, e.g., the arm, leg, chest or waist, and a short air deliverytube can be used to connect the mask with the air flow generator.

2. Description of Related Art

CPAP administration is commonly used to treat respiratory conditionssuch as obstructive sleep apnea. The procedure for CPAP administrationtypically involves sealingly engaging a mask over a patient's nasaland/or oral region and supplying pressurized air to a chamber formed bythe interior of the mask. In conventional systems, the air is suppliedto the mask by an air flow generator typically placed in proximity tothe patient's bed. An air delivery tube is thus needed to deliver airgenerated by the air flow generator to the mask.

There are two main sources of instability of a mask system during use orsleep. Normal patient movement can create instability, for example, apatient rolling on his or her side, which may cause the mask tointerfere with the bedding material. Another concern of using an airdelivery tube that is connected to an apparatus away from the patient isso-called “tubing drag”, which refers to a drag force on the airdelivery tube which is draped over the back or side of the bed. Tubingdrag can be created or complicated by movement of the wearer. Tubingdrag may cause relative movement between the mask seal and the patient'sface during the CPAP administration and produce leaks and/or discomfort.

Another concern involving the air delivery tube is the length thereof(often about 2 meters or more), which may impart a lag in the responseand rise times in delivering pressured air from the air flow generatorto the mask. Increased flow impedance and/or pressure drop due todiameter and length of tubing may also necessitate a larger blower motorto compensate for the pressure drop along the air delivery tube.

U.S. Pat. Nos. 4,590,951; 5,372,130; and 6,435,184 describe masks forsafety applications.

SUMMARY OF THE INVENTION

Aspects of the present invention include addressing the concerns in theart, e.g., by reducing or eliminating the risk of tubing drag duringCPAP administration.

A further aspect of the present invention is to provide the wearer witha greater freedom of movement in bed without compromising seal and/orcomfort.

Another aspect of the present invention includes reducing or eliminatingthe lag in response/rise times in delivering pressured air from thegenerator to the mask.

In one embodiment, a ventilator or CPAP system comprises a mask and anair flow generator, wherein both the mask and the air flow generator areprovided to or on the wearer. In one embodiment, the mask is configuredto be fitted to the patient's face and the air flow generator ismountable to the wearer's body. The air flow generator may be provideddirectly to the mask.

According to one embodiment a CPAP system comprises a face mask and anair flow generator, wherein the air flow generator is mounted on theface mask.

In a further embodiment, a ventilator or CPAP system comprises:

-   (i) a face mask configured to be placed over an area of a wearer's    face, the face mask having:    -   (1) a shell;    -   (2) a cushion provided to a perimeter of the shell to sealingly        connect the face mask to the area of a wearer's face and thereby        form a chamber between the shell and the wearer's face; and    -   (3) an inlet port in the shell to receive a flow of breathable        gas;-   (ii) an air flow generator, said air flow generator being mounted on    said mask and being capable of creating a pressure of about 2-40 cm    H2O in the chamber.

In embodiments, a ventilator or CPAP system includes an air flowgenerator able to be located sufficiently close to a wearer so that anair delivery tube may be less than 1.5 meters in length.

In one embodiment, a ventilator or CPAP system comprises:

a face mask having an inlet port,

an air flow generator having an outlet, and

at least one air delivery tube for delivering breathable gas from thegas outlet to the inlet port,

wherein the at least one air delivery tube does not exceed about 1.5meters in length. The at least one air delivery tube may include two ormore air delivery tubes having a combined overall length of not morethan about 1.5 meters.

In a further embodiment, a ventilator or CPAP system comprises:

-   (i) a face mask having    -   (1) a shell;    -   (2) a cushion provided to the shell to sealingly connect the        face mask to a wearer's face and thereby form a chamber between        the shell and the wearer's face, and;    -   (3) an air inlet port in the shell to receive a flow of        breathable gas;-   (ii) an air flow generator; and-   (iii) an air delivery tube not exceeding 1.5 meters in length, the    air delivery tube being functionally connected to the air inlet port    and the air flow generator to create a pressure of about 2-40 cm H₂O    in the chamber by delivery of breathable gas from the air flow    generator to the air inlet port.

Additional aspects, advantages and features of the present invention areset forth in this specification, and in part will become apparent tothose skilled in the art on examination of the following, or may belearned by practice of the invention. The inventions disclosed in thisapplication are not limited to any particular set of or combination ofaspects, advantages and features. It is contemplated that variouscombinations of the stated aspects, advantages and features make up theinventions disclosed in this application.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a CPAP system according to oneembodiment of the invention;

FIG. 2 is an exploded view of the CPAP system of FIG. 1;

FIG. 3 is a front view taken from an interior of the CPAP system of FIG.1;

FIG. 4 is a rear view taken from an exterior of the CPAP system of FIG.1;

FIG. 5 is a right side view of the CPAP system of FIG. 4;

FIG. 6 is a top view of the CPAP system of FIG. 4;

FIG. 7 is a bottom view of the CPAP system of FIG. 4;

FIG. 8 is a bottom view of a CPAP system according to a furtherembodiment of the invention;

FIG. 9A illustrates a person wearing the CPAP system of FIG. 1;

FIG. 9B illustrates an alternative embodiment of the present invention;

FIG. 10A illustrates a person wearing a CPAP system according to afurther embodiment of the invention;

FIG. 10B is a schematic view of an air flow generator and battery packfor a CPAP system according to an embodiment of the invention;

FIG. 11A represents a person wearing a person wearing a CPAP systemaccording to a further embodiment of the invention; and

FIG. 11B represents a battery pack and strap for a CPAP system accordingto an embodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A CPAP system includes a mask and an air flow generator, wherein the airflow generator is provided to a wearer of the mask. In one embodiment,the air flow generator is mountable to a wearer's body (including awearer's clothing). In another embodiment, the air flow generator ismounted on or provided to the mask.

Figures 1-11B show several embodiments of CPAP systems according to thepresent invention.

Referring to FIG. 1, a CPAP system 10 includes a mask 60 provided with acushion 30 and a shell 46 to form an air chamber in communication withthe airways of a wearer. In this example, the mask 60 covers at leastthe oral and nasal region of a wearer. However, the mask 60 could alsobe a nasal mask and cover, for instance, only the nasal region or onlythe mouth region. In either case, it is preferable that the mask doesnot cover or interfere with the wearer's eyes or vision. The mask mayinclude a vent opening 61 for CO₂ gas washout, and one or more inletports 47 for use in introducing supplemental gas, e.g., oxygen, into theair chamber. The vent opening 61 can be covered with a suitable insert63 or the like to controllably exhaust CO₂. The insert is described inResMed's U.S. Pat. Nos. 6,561,190 and 6,561,191, each incorporatedherein by reference in its entirety.

Mask cushion 30 is preferably made of a soft material (e.g. a rubbermaterial, such as a silicone elastomer) and sealingly connects to thewearer's face to form the air chamber between the wearer's face and themask 60. The shell can be made of a relatively hard plastic, althoughthe shell can be made of the same material as the cushion 30, in someapplications. Examples of cushions 30 are described in, for instance,U.S. Pat. No. 6,513,526, assigned to ResMed Limited, which is herebyincorporated in its entirety by reference. Commercial examples of mask60 include, for instance, the Mirage® Full Face Mask Series II fromResMed Limited (not taking into account adjustments described below inmore detail).

Headgear connectors 50 are provided to the shell 46. Headgear connectorsare designed to receive headgear straps for securing CPAP system 10 to awearer's head (securing straps 55 are shown in FIGS. 9 and 10A).Attached to shell 46 is an extension 72 which will generally be providedwith a resilient pad (not shown) to engage the forehead of the wearer,to provide additional stability. A strap may be provided to eachconnector 50 of the extension 72 for contact with the wearer's crown.Alternatively, or in addition, a strap connector 50 a may be provided tothe extension 72 such that the strap extends over the top of thewearer's head, as shown in FIGS. 9 and 10A.

The air chamber formed between a wearer's face and the interior of mask60 receives breathable gas (e.g. air) through air inlet port 56 (seeFIG. 2), which is designed to be placed in close proximity to (e.g.over) the wearer's oral/nasal region. The breathable gas is supplied byair flow generator 20. In one embodiment, the air flow supplied by airflow generator 20 creates single or variable pressures within the airchamber in the range of 2-40 cm H₂O, for instance 10-28 cm H₂O or 15-20cm H₂O; or relatively constant 10 cm H₂O etc.

Referring to FIG. 2, air flow generator 20 includes, for example, afirst part 90 and a second part 80 that are joined, e.g., by screws 130through bores 134 and 136 to form a housing for impeller 120 and motor100. The parts 80 and 90 may be made from a variety of materials, forinstance from cured resinous materials, from metal (e.g. aluminum), orfrom polymers, e.g. from polyolefins (such as polyethylene orpolypropylene), polycarbonates, or acrylonitrile-butadiene-styrenepolymers (“ABS”).

Motor 100 drives impeller 120. Power is supplied to motor 100 via powercord 110 and the motor is fixedly secured within the impeller housing bytightening screw 132. Examples of electrical motors include, forinstance, miniature bullet motors commercially available from, e.g.,Servo Magnetics Inc., of California. However, various types of motorsmay be used, including for instance pneumatic air powered motors inwhich case the energy source would be a tiny air line instead of anelectrical pulse. The motor assembly may include multiple motors orsingle motors with multiple impellers, double ended impellers, etc.Other possibilities include separate systems which can deliverprescribed air pressure. In another variant, another motor impellerassembly can be utilized to modify, for instance, if an inflatable cuffis provided to react to stimulus or sensed parameters like leakproblems. A separate motor impeller can be used to control positioningof the mask relative to the face or the profile of the cushion seal.

Examples of impellers include, for instance, the S6 CPAP impeller fromResMed Limited. Various impellers may be used, however, such as axialfans, radial fans, centrifugal fans, etc. or any new technology able todeliver the required flow of gas such as air.

The power cord 110 may receive power from any suitable power source,e.g., a wall power outlet, wall mounted transformers, a battery pack orother power storage medium. In one embodiment, power cord 110 includessensor cables to register and/or adjust to data received from sensorsthat may be provided in the mask (e.g. CO₂, O₂, humidity, pressure,flow, and/or temperature sensors). In one embodiment, the monitoring ofsensors occurs via infrared technology or radio waves. A control box maybe provided to adjust, e.g., the motor speed, e.g., for bi-leveltreatment, or other parameters relative to the information receivedthrough the sensors. Other embodiments may be to sense leak and adjustmotor speed and thus delivery pressure or flow accordingly.

The power cord 110 can be connected to a small controller chip (notshown) integrated with an electrical transformer plugged into a poweroutlet. This provides greater flexibility, freedom of movement of thewearer, increased versatility during traveling, etc. Also, there areless components at the mask interface, less overall size of the systemand potentially greater stability. The system may be used for bi-leveltreatment or general ventilatory applications, e.g., where the magnitudeof the pressurized air varies. The system may also provide fasterresponse and rise times and eliminate or at least reduce lag associatedwith air delivery tubes typically having a length of 2 m or more. Thesystem may be easier to use from the perspective of a physician, adealer or clinician, in that only one rather than numerous componentsneed to be fitted for the wearer.

Another embodiment provides the ability to change the strap adjustingpoints; the ability to modify the fit of the mask relative to the facethrough the integrated sensing. For example, if there is a leakgenerated by the mask and a sensor, e.g., a pressure transducer 67 (FIG.4), produces a signal indicative of leaking in the mask, the flowgenerator pressure could be modified. There is also an embodiment wherebladders or cuffs or sections of the mask seal could be modified so thatthe seal profile is modified in certain regions until the leak isresolved and the sensors would provide feedback to the control box thatthe leak is gone and the motor can be controlled to react to thefeedback. See, e.g., U. S. Patent 6,772,760, to ResMed, incorporatedherein by reference in its entirety.

Sensing flow or pressure of the mask system will increase reaction timeand having a motor and an impeller assembly mounted directly into a masksystem would mean that reaction times to pressure and flow changes wouldbe very rapid; therefore there is improved synchrony of delivered gas tothe wearer. Presently, flow generators essentially need to predict whena patient is about to breathe in or have some delay or lag, for example,by pressure sensors mounted to the flow generator. By contrast, oneaspect of the present embodiment allows the mask system to react veryquickly, which provides excellent synchrony of the flow to a patient andthis is key to treat patients especially those with respiratoryinsufficiency who require very good synchrony of flow generator flowpattern to a breathing patient.

Air flow generator 20, e.g., second part 80, is mounted on mask 60,e.g., with four screws 140 (only two are shown in FIG. 2) which extendthrough holes 70 (also, only two shown) into bores 136 (at the oppositeside of screws 130). Of course, a variety of other methods for mountingthe air flow generator 20 on full face mask 60 are feasible, such asusing adhesives, using melt-welding, or integrally forming the shell 46and second part 80 through injection molding. Still another embodimentincludes the ability to easily remove the generator 20 from the mask,e.g., to facilitate cleaning, etc. One or more quick release clips couldbe used for this purpose.

In one embodiment, such as the embodiment shown in FIG. 2, a perforatedscreen 40 (e.g. a perforated metal screen, for instance a perforatedaluminum screen) is placed between inlet port 56 and air flow generator20. The screen separates the outlet 85 (FIG. 3) from air flow generator20 and prevents foreign matter that might enter the air flow generatorfrom reaching the wearer's oral and facial region (air outlet 85 isvisible in FIG. 3 through screen 40). Perforated screen 40 also ensuresthat a wearer's tongue or other body parts larger than perforation sizecannot contact the impeller 120. Examples of perforated screen 40include, for instance, a mesh structure or a thin plate with a pluralityof small bores. This arrangement also prevents any motor or impellerfailure such as breakage from harming the wearer.

FIGS. 3-7 show various views for the CPAP mask 10 in FIGS. 1 and 2. Afurther embodiment is depicted in FIG. 8, where a filter 128 is providedin front of air intake opening 125 (See FIG. 7 for air intake opening125). The filter 128 may be, for instance, a filter to prevent dust fromentering the impeller system (i.e. a dust filter) or a perforatedscreen. Although a perforated screen does not prevent dust from enteringthe impeller system, it is helpful in avoiding, for instance, thewearer's fingers from being able to come into contact with the impeller120. In addition, a perforated screen prevents larger particles fromentering the impeller system. In one embodiment, the CPAP system and/orthe air flow generator has a dust or antimicrobial filter. In a furtherembodiment, the CPAP system and/or air flow generator is absent a dustor antimicrobial filter.

Referring to FIG. 9A, the CPAP system of FIG. 1 is mounted on the faceof a wearer 1 by means of strap 55. The power is provided to the airflow generator 20 by battery pack 150 via power cord 110. Battery pack150 is attached to the wearer's body via strap 160. Advantages of usinga battery pack as the power source include, for instance, the increasedmobility of the wearer. In yet another embodiment illustrated in FIG.9B, power to the air flow generator may be provided via a transformerpower pack 150′ plugged into a wall outlet 163.

FIG. 10A shows an embodiment where impeller system 20A is not directlymounted on mask 60A but instead on a wearer's body via strap 160. Theair outlet of air flow generator 20A is attached to air delivery tube65, which is connected to the air inlet port of full face mask 60A viasocket 64 and coupling tube 62. In one embodiment, air delivery tube 65is shorter than 1.5 meter, for instance 1.0 meter or 0.5 meter. The airdelivery tube may be of any diameter or include multiple air tubes thatare low profile and/or kink resistant, as described in ResMed's U.S.Patent Application No. 60/494,119 filed Aug. 12, 2003, incorporated byreference in its entirety. Power is supplied to air flow generator 20Aby battery pack 150 via power cord 110A. Power pack or flow generatormay also be integrated into one assembly.

In one embodiment, air flow generator 20A and battery pack 150 areattached to strap 160 using clips 162A and 162B (see FIG. 10B). Ofcourse, this embodiment is not limited to such an attachment system andthe air flow generator and/or battery pack may be attached to anysuitable part of a wearer's body (including clothing) by any suitablemeans. For instance, as depicted in FIGS. 11A and 11B, air flowgenerator 20A may also be attached to a wearer's arm using, e.g., aVelcro® strap 160A. The motor assembly, including the impeller, may alsobe attached to other portions of the wearer's body, e.g., the chest viaa strap, the shoulder, etc.

In yet another variant (not shown), the motor assembly may be mounted orprovided or combined to a headgear system, with short tubing running tothe mask. The headgear system could act as form a of vibration damping.Motors invariably vibrate due to imbalances or during motion. Isolatingthis vibration from the wearer will reduce irritation and noise. As thehead is sensitive to vibration, some form of motor and/or impellerisolation is preferable. A damping system may be used; for example avisco-elastic/soft foam “cushion” between the head and flow generatorwould provide some benefit.

In another aspect, a motor can provide a heat sink to provide ability towarm patient breathing air temperature to improve breathing comfort. Anadditional aspect is to be able to control the temperature based onambient conditions, e.g., using a feedback loop. These aspects may beincorporated as part of any of the above embodiments.

While the invention has been described by way of illustrativeembodiments, it is understood that the words which have been used hereinare words of description, rather than words of limitation. Changes maybe made without departing from the scope and spirit of the embodiments.For example, while embodiments have been described as relation to CPAPapplication, it is to be understood that the features described hereinmay also have application in the general ventilation or respiratoryarts. In addition, the system can be used for children and adults of allages.

1. A CPAP system comprising: a mask to be placed over a wearer's face,said mask having a shell; a cushion provided to the shell to sealinglyconnect the mask to the wearer's face and thereby form a chamber betweenthe shell and the wearer's face; and an inlet port in said shell toreceive a flow of breathable gas; and an air flow generator, said airflow generator being mounted on said mask and being capable of creatinga pressure of about 2-40 cm H₂O in said chamber, wherein the air flowgenerator comprises an impeller, a motor to drive the impeller, and ahousing substantially surrounding at least the impeller by conformingsubstantially to a shape and size of the impeller.
 2. The system ofclaim 1, wherein the mask is structured to cover the wearer's nasal andoral region.
 3. The system of claim 1, wherein the mask is constructedto avoid obstruction of the wearer's vision or field of view.
 4. Thesystem of claim 1, wherein said mask is absent a dust filter.
 5. Thesystem of claim 1, wherein the mask is designed to have said inlet portlocated over the wearer's oral region.
 6. The system of claim 1, whereinsaid air flow generator has an air intake opening and an air outlet,said air outlet being positioned co-axial to said air inlet port of themask.
 7. The system of claim 6, wherein a perforated screen ispositioned between said air outlet and said inlet port.
 8. The system ofclaim 1, wherein said cushion comprises a silicone elastomer.
 9. Thesystem of claim 1, wherein said housing forms a contiguous surface withthe shell.
 10. The system of claim 9, further comprising a power cordand a power source, said power cord connecting said power source to saidmotor.
 11. The system of claim 10, wherein said power source is abattery pack.
 12. The system of claim 11, wherein said battery packcomprises at least one fastener to mount the battery pack to saidwearer's body.
 13. The system of claim 1, further comprising aself-contained power source.
 14. The system of claim 1, wherein said airflow generator is selectively detachable from the shell.
 15. The systemof claim 14, wherein the air flow generator and shell are coupled with aquick release clip.
 16. The system of claim 1, further comprising atleast one sensor provided to the mask.
 17. The system of claim 16,wherein the sensor is structured to provide a signal indicative of thefit of the mask.
 18. The system of claim 16, wherein the sensor isstructured to provide a signal indicative of leak on the basis of whichthe flow generator is adapted to be controlled.
 19. The system of claim1, wherein the shell comprises an extension configured to engage thewearer's forehead.
 20. The system of claim 19, wherein the extensioncomprises at least one strap connector configured to receive a headgearstrap.
 21. The system of claim 1, wherein the impeller comprises anaxial fan, a radial fan, or a centrifugal fan.
 22. The system of claim1, further comprising a power cord attached to the motor.
 23. A CPAPsystem, comprising: a mask configured to cover at least a nasal regionof a wearer's face and form an air chamber in communication with theairways of the wearer, the mask comprising a shell and a cushionattached to the shell and configured to sealingly engage the wearer'sface, the shell comprises an outer surface and an inner surface and anair inlet port extending through the shell from the outer surface to theinner surface, the shell further comprising a vent opening extendingthrough the shell from the inner surface to the outer surface; and aflow generator provided on the outer surface of the shell, the flowgenerator comprising a housing having an air inlet and an air outlet,the flow generator further comprising a motor and an impeller configuredto be driven by the motor, the impeller being substantially surroundedby the housing which conforms substantially to a shape and size of theimpeller, and a power cord connected to the motor, wherein the flowgenerator is configured to create a pressure of about 2-40 cm H₂O in theair chamber.
 24. The system of claim 23, further comprising an insertprovided in the vent opening that is configured to control exhaust fromthe mask.
 25. The system of claim 23, further comprising at least onesupplemental inlet port configured to introduce supplemental gas intothe air chamber.
 26. The system of claim 23, wherein the flow generatorhousing is selectively detachable from the shell.
 27. The system ofclaim 23, wherein the flow generator housing comprises a first part anda second part, and the first and second parts are selectively separablefrom each other.
 28. The system of claim 23, further comprising a powersource connected to the power cord.
 29. The system of claim 28, whereinthe power source is configured to be attached to a part of the wearer'sbody, clothing, or a headgear system configured to be attached to themask.
 30. The system of claim 1, wherein the housing comprises a firstpart and a second part, and the first part and the second part areattached to an outer surface of the shell.
 31. The system of claim 1,wherein the housing conforms substantially to a shape and size of themotor.